JP7265838B2 - Converter device, control method and program - Google Patents

Description

The present invention relates to a converter device, control method and program.

Converter devices are used in various fields. Patent Literature 1 describes a technique for applying a converter device to an air conditioner to achieve downsizing and simplification of the device.

JP 2014-150622 A

By the way, in the motor drive device described in Patent Document 1, a current corresponding to the differential voltage between both ends of the reactor flows through the reactor in the converter device. Therefore, in the motor driving device described in Patent Document 1, the distortion of the input current becomes large due to the distortion of the power supply voltage.

Therefore, in a converter device through which a current flows according to the voltage difference between both ends of the reactor, such as the reactor in the converter device described in Patent Document 1, it is desirable to reduce the distortion of the input current caused by the distortion of the power supply voltage. There was a demand for technology that could

An object of the present invention is to provide a converter device, a control method, and a program that can solve the above problems.

According to a first aspect of the present invention, a converter device includes a rectifier circuit that rectifies an AC voltage containing harmonic components with respect to a single frequency component output from an AC power supply into a DC voltage, and a first a reactor to which a terminal is connected, a diode whose anode is connected to a second terminal of the reactor, a first terminal to which the cathode of the diode is connected, and a second terminal to which a reference potential of the rectifier circuit is connected a first terminal is connected to a second terminal of the reactor, a second terminal is connected to a terminal serving as a reference potential of the rectifier circuit, and an ON state is applied according to a control signal applied to a third terminal; A switching element that controls the current flowing to the capacitor by switching between and off state, and a voltage waveform of the AC voltage output by the AC power supply, or a half-wave after rectification of the AC voltage output by the AC power supply. A voltage detection unit that detects a voltage waveform, a waveform obtained by taking the absolute value of the voltage waveform detected by the voltage detection unit, and a triangular wave that is a predetermined reference voltage waveform that serves as a reference are compared to determine the triangular wave. generating a high-level switching signal when the waveform is greater than the waveform having the absolute value, and generating a low-level switching signal when the triangular wave is less than the waveform having the absolute value; a control signal generation unit that generates a control signal for controlling switching between an ON state and an OFF state of the switching element .

According to a second aspect of the present invention, in the converter device according to the first aspect, the voltage detection section detects a half-wave voltage waveform after rectification of the AC voltage output from the AC power supply, The signal generator generates a waveform obtained by taking the absolute value of the detected voltage waveform and a triangular waveform, which is a predetermined reference voltage waveform, during the period in which the voltage detector detects the rectified voltage waveform. and generating a High level switching signal when the triangular wave waveform is greater than the waveform having the absolute value, and Low level switching signal when the triangular wave waveform is less than or equal to the waveform having the absolute value The control signal is generated by generating a signal, and the generated control signal is output to the switching element in a period in which the rectified voltage waveform becomes 0 following a period in which the rectified voltage waveform is detected. may be

According to a third aspect of the present invention, a control method using a converter device includes a rectifier circuit for rectifying an AC voltage containing harmonic components with respect to a single frequency component output from an AC power supply into a DC voltage, and an output of the rectifier circuit. a reactor having a first terminal connected to a second terminal of the reactor; a diode having an anode connected to a second terminal of the reactor; a cathode of the diode having a first terminal connected to a cathode thereof; A first terminal is connected to a second terminal of the capacitor and the reactor to which the terminal is connected, a second terminal is connected to a terminal serving as a reference potential of the rectifier circuit, and a control signal is applied to the third terminal. a switching element that controls the current flowing to the capacitor by switching between an on state and an off state, wherein the voltage waveform of the alternating voltage output by the alternating current power supply, or the alternating current Detecting a half-wave voltage waveform after rectification of the AC voltage output from the power supply, a waveform obtained by taking the absolute value of the detected voltage waveform, and a triangular waveform that is a predetermined reference voltage waveform that serves as a reference. and generating a high-level switching signal when the triangular waveform is greater than the waveform with the absolute value, and generating a low-level switching signal when the triangular waveform is less than or equal to the waveform with the absolute value. and generating a control signal for controlling switching of the switching element between an ON state and an OFF state by generating a switching signal of .

According to the fourth aspect of the present invention, the program comprises: a rectifier circuit for rectifying an AC voltage containing harmonic components with respect to a single frequency component output from an AC power supply into a DC voltage; a diode whose anode is connected to the second terminal of the reactor; a first terminal connected to the cathode of the diode; and a second terminal connected to a terminal serving as a reference potential of the rectifier circuit. a capacitor having a first terminal connected to a second terminal of the reactor, a second terminal connected to a terminal serving as a reference potential of the rectifier circuit, and an ON state according to a control signal applied to a third terminal; a voltage waveform of the AC voltage output by the AC power supply, or the AC voltage output by the AC power supply, to a computer of a converter device comprising a switching element that controls the current flowing to the capacitor by switching between an off state and an off state; comparing the absolute value of the detected voltage waveform with a triangular waveform that is a predetermined reference voltage waveform; generating a high-level switching signal when the triangular wave waveform is greater than the waveform having the absolute value, and generating a low-level switching signal when the triangular wave waveform is equal to or less than the waveform having the absolute value; and generating a control signal for controlling switching between the ON state and the OFF state of the switching element .

According to the converter device, the control method, and the program according to the embodiments of the present invention, it is possible to reduce the distortion of the input current caused by the distortion of the power supply voltage in the converter device in which the current corresponding to the differential voltage across the reactor flows.

It is a figure which shows the structure of the motor drive device by one Embodiment of this invention. It is a figure which shows the structure of the converter control part by one Embodiment of this invention. FIG. 4 is a diagram for explaining generation of switching signals in an embodiment of the present invention; FIG. 4 is a diagram for explaining generation of switching signals in an embodiment of the present invention; It is a figure which shows the processing flow of the converter apparatus by one Embodiment of this invention. 1 is a schematic block diagram showing a configuration of a computer according to at least one embodiment; FIG.

<Embodiment>
Hereinafter, embodiments will be described in detail with reference to the drawings.
A motor drive device according to an embodiment of the present invention will be described.
FIG. 1 is a diagram showing the configuration of a motor drive device 1 according to one embodiment of the present invention. The motor drive device 1 is a device that converts AC power from an AC power supply 4 into DC power, converts the DC power into three-phase AC power, and outputs the three-phase AC power to a compressor motor 20 . The motor drive device 1 includes a converter device 2 and an inverter device 3, as shown in FIG.

The converter device 2 is a device that converts AC power from the AC power supply 4 into DC power and outputs the DC power to the inverter device 3 . Converter device 2 includes rectifier circuit 5 , switching circuit 10 a , switching circuit 10 b , smoothing capacitor 12 , converter control section 15 , and voltage detection section 30 .
The rectifier circuit 5 includes an input terminal, an input-side reference terminal, an output terminal, and an output-side reference terminal. The potential of the reference terminal on the input side is a potential that serves as a reference for the potential of the input terminal. The potential of the reference terminal on the output side is a potential that serves as a reference for the potential of the output terminal. The rectifier circuit 5 converts the AC power input from the AC power supply 4 into DC power, and outputs the DC power to the switching circuits 10a and 10b.

The switching circuit 10 a causes current to flow through the smoothing capacitor 12 and generates a voltage to be input to the inverter device 3 . The switching circuit 10a includes a reactor 6a, a diode 7a, and a switching element 8a.

The reactor 6a includes a first terminal and a second terminal.
The diode 7a has an anode terminal and a cathode terminal.
The switching element 8a has a first terminal, a second terminal, and a third terminal. The switching element 8a switches between an on-state period and an off-state period according to a signal received by the first terminal, thereby controlling the current flowing from the second terminal to the third terminal. Change the value of the current that flows. Examples of the switching element 8a include a field effect transistor (FET), an IGBT (Insulated Gate Bipolar Transistor), and the like. When the switching element 8a is, for example, an nMOS transistor, the first terminal of the switching element 8a is the gate terminal, the second terminal is the source terminal, and the third terminal is the drain terminal.

Similar to the switching circuit 10a, the switching circuit 10b causes current to flow through the smoothing capacitor 12 and generates a voltage to be input to the inverter device 3. FIG. The switching circuit 10b includes a reactor 6b, a diode 7b, and a switching element 8b.

The reactor 6b has a first terminal and a second terminal.
The diode 7b has an anode terminal and a cathode terminal.
The switching element 8b, like the switching element 8a, has a first terminal, a second terminal, and a third terminal. The switching element 8b switches between an on-state period and an off-state period in accordance with a signal received by the first terminal, thereby controlling the current flowing from the second terminal to the third terminal. Change the value of the current that flows. A field effect transistor, an IGBT, or the like can be used as the switching element 8b. When the switching element 8b is, for example, an nMOS transistor, the first terminal of the switching element 8b is the gate terminal, the second terminal is the source terminal, and the third terminal is the drain terminal.

The smoothing capacitor 12 has a first terminal and a second terminal. Smoothing capacitor 12 receives current from both switching circuit 10a and switching circuit 10b. That is, the voltage input to the inverter device 3 is determined by the sum of current values flowing through the smoothing capacitor 12 from both the switching circuits 10a and 10b.

The voltage detection section 30 has a first input terminal, a second input terminal, and an output terminal. The voltage detection unit 30 detects an input voltage that the AC power supply 4 inputs to the rectifier circuit 5 . Voltage detection unit 30 provides information on the detected input voltage to converter control unit 15 .
Converter control unit 15 includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal. Converter control unit 15 receives input voltage information from voltage detection unit 30 via the first input terminal and observes the input voltage waveform. The converter control section 15 controls the switching circuit 10a via the first output terminal. Also, the converter control unit 15 controls 10b through the second output terminal.

The AC power supply 4 has an output terminal and a reference terminal. AC power supply 4 supplies AC power to converter device 2 .

The zero-cross detector 17 has a first input terminal, a second input terminal, and an output terminal. The zero-cross detector 17 detects the zero-cross points of the voltage output from the AC power supply 4 via the first input terminal and the second input terminal. The zero-cross point indicates the time when the voltage output from the AC power supply 4 crosses zero volts, and this time is the reference time for the processing of the motor drive device 1 . The zero-cross detector 17 generates a zero-cross signal including information on zero-cross points. Zero-cross detector 17 outputs a zero-cross signal to converter controller 15 via an output terminal.

The inverter device 3 is a device that converts the DC power output from the converter device 2 into three-phase AC power and outputs the three-phase AC power to the compressor motor 20 . The inverter device 3 includes a bridge circuit 18 and an inverter control section 19 .
The bridge circuit 18, as shown in FIG. 1, has an input terminal, a first output terminal, a second output terminal, a third output terminal, and a reference terminal. The potential of the reference terminal is a potential that serves as a reference for the potentials of the input terminal, the first output terminal, the second output terminal, and the third output terminal. The bridge circuit 18 includes switching elements 181 , 182 , 183 , 184 , 185 and 186 . The bridge circuit 18 is configured by pairs of switching elements 181 and 182, switching elements 183 and 184, and switching elements 185 and 186, respectively. Each of the switching elements 181-186 has a first terminal, a second terminal and a third terminal. Each of the switching elements 181 to 186 controls the current flowing from the second terminal to the third terminal by switching between the ON state period and the OFF state period according to the signal received by the first terminal, Three-phase AC power for driving the compressor motor 20 is generated, and the generated three-phase AC power is output to the compressor motor 20 . Examples of the switching elements 181, 182, 183, 184, 185, 186 include power field effect transistors, IGBTs, and the like.

The inverter control unit 19 has a first output terminal, a second output terminal, a third output terminal, a fourth output terminal, a fifth output terminal, and a sixth output terminal. A first output terminal of the inverter control unit 19 is a terminal for outputting to the first terminal of the switching element 181 a gate drive signal for switching between the ON state period and the OFF state period of the switching element 181 . The second output terminal of the inverter control unit 19 is a terminal for outputting to the first terminal of the switching element 182 a gate drive signal for switching between the ON state period and the OFF state period of the switching element 182 . A third output terminal of the inverter control unit 19 is a terminal for outputting to a first terminal of the switching element 183 a gate drive signal for switching between the ON state period and the OFF state period of the switching element 183 . A fourth output terminal of the inverter control unit 19 is a terminal for outputting to the first terminal of the switching element 184 a gate drive signal for switching between the ON state period and the OFF state period of the switching element 184 . A fifth output terminal of the inverter control unit 19 is a terminal for outputting to a first terminal of the switching element 185 a gate driving signal for switching between the ON state period and the OFF state period of the switching element 185 . A sixth output terminal of the inverter control unit 19 is a terminal for outputting to a first terminal of the switching element 186 a gate drive signal for switching between the ON state period and the OFF state period of the switching element 186 . 1, the first to sixth output terminals of the inverter control section 19 are omitted. In FIG. 1, the gate drive signals output from the first to sixth output terminals of the inverter control section 19 to the bridge circuit 18 are collectively indicated as the gate drive signal Spwm. The inverter control unit 19 controls opening and closing of switching elements in the bridge circuit 18 . The inverter control unit 19 generates a gate drive signal Spwm for the switching elements 181 to 186 based on, for example, a required rotational speed command input from a host device (not shown). The inverter control section 19 supplies the gate drive signal Spwm to the bridge circuit 18 through the first to sixth output terminals. Examples of specific methods of inverter control include vector control, sensorless vector control, V/F (Variable Frequency) control, overmodulation control, and one-pulse control.

The input terminal of the rectifier circuit 5 is connected to the output terminal of the AC power supply 4 , the first input terminal of the zero-cross detection section 17 and the first input terminal of the voltage detection section 30 . The reference terminal on the input side of the rectifier circuit 5 is connected to the reference terminal of the AC power supply 4 , the second input terminal of the zero-cross detector 17 , and the second input terminal of the voltage detector 30 . An output terminal of the rectifier circuit 5 is connected to a first terminal of the reactor 6a and a first terminal of the reactor 6b. Reference terminals on the output side of the rectifier circuit 5 are the third terminal of the switching element 8a, the third terminal of the switching element 8b, the second terminal of the smoothing capacitor 12, and the reference terminals of the inverter device 3 (switching elements 182 and 184). , 186).
A second terminal of the reactor 6a is connected to the anode terminal of the diode 7a and the second terminal of the switching element 8a. A second terminal of reactor 6b is connected to an anode terminal of diode 7b and a second terminal of switching element 8b.
The cathode terminal of diode 7a is connected to the cathode terminal of diode 7b, the first terminal of smoothing capacitor 12, and the input terminal of inverter device 3 (the second terminals of switching elements 181, 183, and 185).
A first terminal of switching element 8 a is connected to a first output terminal of converter control section 15 . A first terminal of switching element 8 b is connected to a second output terminal of converter control section 15 .
A first terminal of converter control unit 15 is connected to an output terminal of voltage detection unit 30 . A second terminal of converter control section 15 is connected to an output terminal of zero-cross detection section 17 .
A first terminal of the switching element 181 is connected to a first output terminal of the inverter control section 19 . A first terminal of the switching element 182 is connected to a second output terminal of the inverter control section 19 . A first terminal of the switching element 183 is connected to a third output terminal of the inverter control section 19 . A first terminal of the switching element 184 is connected to a fourth output terminal of the inverter control section 19 . A first terminal of the switching element 185 is connected to a fifth output terminal of the inverter control section 19 . A first terminal of the switching element 186 is connected to a sixth output terminal of the inverter control section 19 .
The third terminal of switching element 181 is connected to the second terminal of switching element 182 and the first terminal of compressor motor 20 . The third terminal of switching element 183 is connected to the second terminal of switching element 184 and the second terminal of compressor motor 20 . The third terminal of switching element 185 is connected to the second terminal of switching element 186 and the first terminal of compressor motor 20 .

It should be noted that When the inverter control unit 19 controls opening and closing of the switching elements in the bridge circuit 18 as described above, a DC voltage detection unit and a motor current detection unit are provided as described in Patent Document 1. good too.
The DC voltage detector is a detector that detects the input DC voltage Vdc of the bridge circuit 18 .
The motor current detector is a detector that detects phase currents iu, iv, and iw flowing through the compressor motor 20 . The motor current detector inputs these detected values Vdc, iu, iv, and iw to the inverter controller 19 . The motor current detector may detect the current flowing in the negative power line between the bridge circuit 18 and the smoothing capacitor 12 and obtain the phase currents iu, iv, and iw from this detection signal.

FIG. 2 is a functional block diagram of converter control section 15. As shown in FIG.
The converter control unit 15 includes a waveform observation unit 21, a control signal generation unit 22, and a storage unit 23, as shown in FIG.

Waveform observation section 21 receives from zero-cross detection section 17 a zero-cross signal indicating a zero-cross point of AC power supply 4 detected by zero-cross detection section 17 . Waveform observation section 21 receives an input voltage waveform from voltage detection section 30 . The waveform observing section 21 observes the input voltage waveform with reference to the zero cross point.

The control signal generator 22 generates a first switching signal Sg1 for controlling the switching circuit 10a and a second switching signal Sg2 for controlling the switching circuit 10b.
Specifically, the control signal generator 22 generates a predetermined triangular wave as shown in FIGS. 3(a) and 3(c). The predetermined triangular wave is a signal with a waveform that serves as a reference when generating the control signal from the input voltage waveform. Then, the control signal generator 22 compares the triangular wave and the input voltage waveform, and based on the comparison result, generates a first switching signal Sg1 for controlling the switching element 8a as shown in FIGS. 3(b) and 3(d). and a second switching signal Sg2 for controlling the switching element 8b.
Specifically, the control signal generator 22 converts the input voltage waveform in which the third harmonic distortion is superimposed on the fundamental wave of the AC power supply 4 shown in FIG. 4(a), as shown in FIG. and compares the absolute value with the reference waveform (triangular wave), generates a High level switching signal when the reference waveform is greater than the input voltage waveform, and generates a Low level switching signal when the reference waveform is less than or equal to the input voltage waveform. Generate a level switching signal. The control signal generator 22 generates the first switching signal Sg1 and the second switching signal Sg2 using the input voltage waveform including the input voltage distortion that causes the input current distortion. Therefore, information about the input current distortion is reflected in the first switching signal Sg1 and the second switching signal Sg2. The control signal generator 22 can cancel the distortion in the input current by controlling the switching element 8a with the first switching signal Sg1 and controlling the switching element 8b with the second switching signal Sg2.
The example of the input voltage waveform shown here shows the case where the fundamental wave of the AC power supply 4 is superimposed with the third harmonic distortion. Harmonic distortions such as second harmonics are superimposed in a complex manner and change from moment to moment. The waveform in which the third harmonic distortion is superimposed on the fundamental wave of the AC power supply 4 shown in FIG. 3 is an extreme example with many third harmonic distortion components. The proportion of harmonic distortion components is less than in this example. Therefore, the input voltage waveform becomes a waveform closer to the case of only the fundamental wave than the waveform shown in FIG.
Storage unit 23 stores various information necessary for processing performed by converter control unit 15 .

Next, processing of the motor drive device 1 according to one embodiment of the present invention will be described.
Here, the processing flow of the converter device 2 shown in FIG. 5 will be described.
Note that the processing of the converter device 2 shown in FIG. 5 is processing performed when an input current is flowing.

The zero-cross detector 17 detects the zero-cross point of the voltage output from the AC power supply 4 via the first input terminal and the second input terminal (step S1). The zero-cross detector 17 generates a zero-cross signal including information on zero-cross points (step S2). Zero-cross detector 17 outputs a zero-cross signal to converter controller 15 via an output terminal.

Waveform observation section 21 receives a zero-cross signal from zero-cross detection section 17 . The waveform observation unit 21 identifies zero-crossing points from the received zero-crossing signal (step S3). Waveform observation unit 21 receives an input voltage from voltage detection unit 30 (step S4). Waveform observing section 21 observes the received input voltage waveform with reference to the zero cross point. The waveform observing section 21 outputs the observed input voltage waveform to the control signal generating section 22 . At this time, the input voltage waveform output from the waveform observing section 21 to the control signal generating section 22 includes information on the zero cross points.

The control signal generator 22 generates a predetermined triangular wave that serves as a reference waveform (step S5). Control signal generator 22 receives an input voltage waveform from waveform observer 21 . The control signal generator 22 matches the timing of the input voltage waveform with the triangular wave generated based on the zero crossing points included in the input voltage waveform, and compares the input voltage waveform and the triangular wave (step S6). Based on the comparison result, the control signal generator 22 generates a first switching signal Sg1 for controlling the switching element 8a and a second switching signal Sg2 for controlling the switching element 8b (step S7). Specifically, the control signal generator 22 generates a high-level switching signal when the triangular wave is larger than the input voltage waveform. Also, the control signal generator 22 generates a low-level switching signal when the triangular wave is equal to or less than the input voltage waveform.
The control signal generator 22 outputs the generated first switching signal Sg1 to the switching element 8a. Further, the control signal generator 22 outputs the generated second switching element Sg2 to the switching element 8b.
The switching element 8a is turned on or off according to the first switching signal Sg1. Also, the switching element 8b is turned on or off according to the second switching signal Sg2.

The motor drive device 1 according to one embodiment of the present invention has been described above.
In the motor driving device 1 according to one embodiment of the present invention, the control signal generator 22 (controller) compares the input voltage waveform supplied from the AC power supply 4 to the rectifier circuit with a triangular wave as a reference waveform. The control signal generator 22 generates the first switching signal and the second switching signal based on the comparison result.
Input current distortion is caused by distortion of the input voltage waveform. Therefore, by using the input voltage waveform, the control signal generation unit 22 compares the first switching signal and the second switching signal, in which information about the input current distortion is reflected, with the input voltage waveform and the triangular wave serving as the reference waveform. It can be generated immediately according to the result.

In one embodiment of the present invention, the voltage detection unit 30 detects the voltage waveform at the input of the rectifier circuit 5 as the input voltage waveform. However, in another embodiment of the present invention, the voltage detection section 30 may detect the voltage waveform at the output of the rectifier circuit 5 as the input voltage waveform. When the voltage detection unit 30 detects a voltage waveform at the output of the rectifier circuit 5 as the input voltage waveform, the input voltage waveform is a half-wave waveform. In this case, the control signal generator 22 may, for example, repeatedly apply the switching signal generated during the half-wave waveform detection period also during the non-detection period of the input voltage waveform.

Note that in another embodiment of the present invention, for example, the waveform observation unit 21 performs FFT (Fast Fourier Transform) operation on the input voltage waveform, decomposes the input voltage signal into frequency components, and determines the input current distortion. A signal obtained by synthesizing only the signals of the frequency components to be corrected is output to the control signal generator 22 . Then, the control signal generator 22 may generate a switching signal for a signal obtained by synthesizing only signals of frequency components for which input current distortion is to be corrected.
Alternatively, the waveform observation unit 21 may perform FFT (Fast Fourier Transform) calculations on the input voltage waveform, and effectively use the input voltage signal decomposed for each frequency component for processing other than distortion correction.

In one embodiment of the present invention, the AC power supply 4 is a single-phase power supply, but in another embodiment of the present invention, the AC power supply 4 may be a three-phase power supply.

Note that the storage unit 23 and other storage units in each embodiment of the present invention may be provided anywhere as long as appropriate information transmission/reception is performed. Further, the storage unit 23 and other storage units may have a plurality of storage units within a range where appropriate information transmission/reception is performed, and store data in a distributed manner.

It should be noted that the order of the processes in the embodiment of the present invention may be changed as long as appropriate processes are performed.

Each of the storage unit 23 and storage devices (including registers and latches) in the embodiment of the present invention may be provided anywhere as long as appropriate information transmission/reception is performed. In addition, each of the storage unit 23 and the storage device may exist in a plurality and store data in a distributed manner within a range where appropriate information transmission/reception is performed.

Although the embodiments of the present invention have been described, the converter control section 15, the inverter control section 19, and other control devices described above may have a computer system therein. The process of the above-described processing is stored in a computer-readable recording medium in the form of a program, and the above-described processing is performed by reading and executing this program by a computer. Specific examples of computers are shown below.
FIG. 6 is a schematic block diagram showing the configuration of a computer according to at least one embodiment.
The computer 50 includes a CPU 60, a main memory 70, a storage 80, and an interface 90, as shown in FIG.
For example, each of the above-described converter control unit 15 , inverter control unit 19 , and other control devices is implemented in computer 50 . The operation of each processing unit described above is stored in the storage 80 in the form of a program. The CPU 60 reads out a program from the storage 80, develops it in the main memory 70, and executes the above processes according to the program. In addition, the CPU 60 secures storage areas corresponding to the storage units described above in the main memory 70 according to the program.

Examples of the storage 80 include HDD (Hard Disk Drive), SSD (Solid State Drive), magnetic disk, magneto-optical disk, CD-ROM (Compact Disc Read Only Memory), DVD-ROM (Digital Versatile Disc Read Only Memory). , semiconductor memory, and the like. The storage 80 may be an internal medium directly connected to the bus of the computer 50, or an external medium connected to the computer 50 via the interface 90 or communication line. Further, when this program is distributed to the computer 50 via a communication line, the computer 50 receiving the distribution may develop the program in the main memory 70 and execute the above process. In at least one embodiment, storage 80 is a non-transitory, tangible storage medium.

Further, the program may implement part of the functions described above. Furthermore, the program may be a file capable of realizing the above functions in combination with a program already recorded in the computer system, that is, a so-called difference file (difference program).

While several embodiments of the invention have been described, these embodiments are examples and do not limit the scope of the invention. Various additions, omissions, replacements, and modifications may be made to these embodiments without departing from the scope of the invention.

Reference Signs List 1 Motor drive device 2 Converter device 3 Inverter device 4 AC power supply 5 Rectifier circuits 6a, 6b Reactors 7a, 7b Diodes 8a, 8b Switching elements 10a, 10b Switching circuit 12 Smoothing capacitor 15 Converter control unit 17 Zero cross detection unit 21 Waveform observation unit 22 Control signal generation unit 23 Memory unit 30 Voltage detection unit 50 Computer 60 CPU
70 Main memory 80 Storage 90 Interface Lp Positive electrode bus

Claims (4)

a rectifier circuit that rectifies an AC voltage containing harmonic components with respect to a single frequency component output from an AC power supply into a DC voltage;
a reactor having a first terminal connected to the output of the rectifier circuit;
a diode whose anode is connected to the second terminal of the reactor;
a capacitor having a first terminal connected to the cathode of the diode and having a second terminal connected to a terminal serving as a reference potential of the rectifier circuit;
A first terminal is connected to a second terminal of the reactor, a second terminal is connected to a terminal serving as a reference potential of the rectifier circuit, and the reactor is turned on and off according to a control signal applied to the third terminal. a switching element that controls the current flowing to the capacitor by switching;
a voltage detection unit that detects a voltage waveform of the AC voltage output by the AC power supply or a half-wave voltage waveform after rectification of the AC voltage output by the AC power supply;
A waveform obtained by taking the absolute value of the voltage waveform detected by the voltage detection unit is compared with a triangular waveform that is a predetermined reference voltage waveform as a reference, and the waveform of the triangular wave is compared with the waveform having the absolute value. is large, a high-level switching signal is generated, and when the waveform of the triangular wave is equal to or less than the waveform obtained by taking the absolute value, a low-level switching signal is generated. a control signal generator that generates a control signal that controls switching;
A converter device comprising: The voltage detection unit is
detecting a half-wave voltage waveform after rectification of the AC voltage output by the AC power supply;
The control signal generator is
During the period in which the voltage detection unit detects the rectified voltage waveform, the waveform obtained by taking the absolute value of the detected voltage waveform is compared with a triangular waveform that is a predetermined reference voltage waveform as a reference. generating a high-level switching signal when the triangular wave waveform is greater than the waveform having the absolute value, and generating a low-level switching signal when the triangular wave waveform is equal to or less than the waveform having the absolute value; and outputting the generated control signal to the switching element during a period in which the rectified voltage waveform becomes 0 following a period in which the rectified voltage waveform is detected.
The converter device according to claim 1. A rectifier circuit for rectifying an AC voltage including harmonic components with respect to a single frequency component output from an AC power supply into a DC voltage, a reactor having a first terminal connected to the output of the rectifier circuit, and a second terminal of the reactor. a capacitor having a first terminal connected to the cathode of the diode and a second terminal connected to a terminal serving as a reference potential of the rectifier circuit; and a first terminal connected to the second terminal of the reactor . A second terminal is connected to a terminal serving as a reference potential of the rectifier circuit, and switching between an ON state and an OFF state according to a control signal applied to the third terminal causes current flowing through the capacitor to be reduced. A control method by a converter device comprising a switching element to be controlled,
detecting a voltage waveform of the AC voltage output by the AC power supply, or a half-wave voltage waveform after rectification of the AC voltage output by the AC power supply;
comparing a waveform obtained by taking the absolute value of the detected voltage waveform with a triangular waveform that is a predetermined reference voltage waveform;
When the waveform of the triangular wave is larger than the waveform of which the absolute value is taken, a high level switching signal is generated, and when the waveform of the triangular wave is equal to or less than the waveform of which the absolute value is taken, a low level switching signal is generated. generating a control signal for controlling switching between the ON state and the OFF state of the switching element by
A control method by a converter device including A rectifier circuit for rectifying an AC voltage including harmonic components with respect to a single frequency component output from an AC power supply into a DC voltage, a reactor having a first terminal connected to the output of the rectifier circuit, and a second terminal of the reactor. a capacitor having a first terminal connected to the cathode of the diode and a second terminal connected to a terminal serving as a reference potential of the rectifier circuit; and a first terminal connected to the second terminal of the reactor . A second terminal is connected to a terminal serving as a reference potential of the rectifier circuit, and switching between an ON state and an OFF state according to a control signal applied to the third terminal causes current flowing through the capacitor to be reduced. A computer of a converter device comprising a switching element to control ,
detecting a voltage waveform of the AC voltage output by the AC power supply, or a half-wave voltage waveform after rectification of the AC voltage output by the AC power supply;
comparing a waveform obtained by taking the absolute value of the detected voltage waveform with a triangular waveform that is a predetermined reference voltage waveform;
When the waveform of the triangular wave is larger than the waveform of which the absolute value is taken, a high level switching signal is generated, and when the waveform of the triangular wave is equal to or less than the waveform of which the absolute value is taken, a low level switching signal is generated. generating a control signal for controlling switching between the ON state and the OFF state of the switching element by
program to run.

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